Cutting portions of cutting tools for machining metallic materials are easily worn out due to the friction occurring during machining. Thus, when the cutting portions are worn out, replacing only the worn cutting portions is absolutely advantageous in cutting operations. As such, in a cutting operation, a method of detachably mounting a replaceable cutting insert in the body of the cutting tool is generally used.
A clamping method of using a screw and a clamping method of using a wedge are typical examples of methods to clamp the cutting insert in the cutter body. The clamping method of using a screw is to form concentric screw holes in both the cutting insert and the insert seat, as well as to clamp a screw into both holes to secure the cutting insert in the cutting tool. It is the simplest clamping method. However, the method of clamping the cutting insert by using a screw is not so efficient when machining large workpieces such as a part of a vessel. This is because when separating the worn cutting insert from the cutting tool, the worker has to separate the cutting tool body from the machining equipment due to the difficulty in accessing the tool for disassembling the screw. Since the cutting tool body for machining large workpieces is generally large, separating the cutting tool from the machining equipment or mounting it on the machining equipment is very troublesome.
Thus, to machine the large workpieces, the workers prefer to use the wedge clamping method since there is no need to separate the tool body from the equipment when replacing the worn cutting insert. The cutting insert clamping structure, which uses the wedge, is disclosed in Korean Patent Laid-Open Publication No. 1996-703697. Present FIGS. 1 and 2 illustrate such cutting tool. A milling cutter 110 includes a plurality of slots 130, which are arranged at same intervals around the outer circumference of the cylindrical cutter body 111. An adapter seat 140 is recessed within one side surface 133 of the slot 130. A wedge 150 is received in the slot 130, while an adapter 160 is received in the adapter seat 140. A cutting insert 120 is seated and fixed on the top surface of the adapter 160. When the adapter 160, on which the cutting insert is seated, is mounted on the adapter seat 140, the top surface of the cutting insert contacts one side surface of the wedge 150. A screw 170 is clamped into a screw hole 172 of the slot 130 through a screw hole 171 of the wedge 150. As the screw 170 advances into the screw hole of the slot 130, the wedge 150 is pushed toward the screw hole of the slot 130. Since the wedge 150 tapers inwardly, the cutting insert 120 is clamped in the adapter 160 by the wedge 150 as the wedge 150 advances toward the screw hole of the slot 130. Disclosure of Invention